Wikijunior:Solar System/Glossary
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| The Solar System |
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Introduction |
A glossary of words used in this book:
- Antimatter: the opposite of normal matter. Not usually found outside of a laboratory. When mixed with matter they cancel each other out and release lots of energy.
- Arachnoid: a scientific term for something shaped like a spider, like the legend of the weaving contest.
- Asteroid: a large rocky object that orbits a star, but is too small to be a planet. It is found in space.
- Astronomer: a person who studies stars and planets. Also a person who explores new planets and solar systems.
- Astronaut: a person who travels beyond the atmosphere of the Earth.
- Atmosphere: a layer of gases around a planet.
- Atom: a very tiny particle that is the basic building block of matter. It is the tiniest thing on Earth.
- Basalt lava: molten basalt, a kind of rock from a volcano.
- Belt: A name used for bands of dark-colored cloud layers on Jupiter.
- Binoculars: a folding pair of small telescopes with an eyepiece for each eye.
- Carbon dioxide: a gas that animals breathe out and plants take in.
- Carbonaceous chondrite: A type of meteorite that contains a lot of water and organic compounds.
- Centaur: an icy planetoid that orbits the Sun between Jupiter and Neptune.
- Channel: a groove in the surface of something.
- Comet: a small icy object orbiting a star.
- Conjunction: when two objects orbiting the same body come closest together.
- Continent: a huge landmass on a planet, usually made of tectonic plates that have locked together.
- Convection: a type of movement in a gas or liquid that carries heat toward a cooler location. When the gas or liquid cools, it sinks back down again.
- Core: the center of a planet or star.
- Corona: a region of very hot gas that surrounds the photosphere of a star.
- Crater: a dent in a planet's surface made by a meteorite falling on it.
- Crust: the outermost layer of a planet's surface.
- Dwarf planet: a rounded body that is in orbit around the Sun. It is not a moon and it is not big enough to sweep up the other objects along its orbit.
- Eclipse: the shadow made when one object comes between another object and the Sun.
- Energy: what you use to do work.
- Environment: the conditions on a planet.
- Equator: an imaginary line around a planet, perpendicular to the axis of rotation.
- Erosion: the slow wearing away of a surface, usually from wind, water, and temperature changes.
- Galaxy: a huge mix of gas, dust, stars, planets and other objects that are held together by their own gravity.
- Gas giant: one of the four outer planets made out of giant balls of gas.
- Gravity: the force that pulls on anything with mass (see the About gravity, mass, and weight section).
- Hemisphere: one half of a planet's surface.
- Ice cap: A huge body of ice at the pole of a planet.
- Lagrange point: the places where the gravity from two orbiting objects balance each other.
- Lava: molten rock above a planet's surface.
- Latin: the language of the Roman Empire that was later used by scientists to name things.
- Mantle: a layer of molten rock below a planet's crust.
- Maria: a large sea of magma that has cooled into solid rock.
- Mass: the amount of matter that something is made of (see the About gravity, mass, and weight section).
- Matter: a scientific word for 'stuff'.
- Meteor: a small or medium-size rock from space that has entered a planet's atmosphere but has not reached the ground.
- Meteor shower: a large number of meteors that enter a planet's atmosphere at about the same time.
- Meteorite: A meteorite that made it through a planet's atmosphere and landed on the ground.
- Methane: a gas that makes up most of the gas giants.
- Near Earth asteroid: an asteroid that has an orbit that brings it very close to the earth.
- Newton: a unit of measurement the describes how hard gravity is pulling you down (see the About gravity, mass, and weight section).
- Observatory: A special building where astronomers keep their telescopes ready for use.
- Orbit: the path that an object takes around a larger object.
- Orbit System: a planet and its moons rotating around a star.
- Organic compounds: compounds (collections of atoms) containing carbon.
- Phase: how a planet or moon looks to us at some part of its orbit, when it is lit by the Sun.
- Planet: the celestial body that has a greater mass than all other objects of the same orbit system together and that describes a well-defined, special orbit around a star.
- Planetary nebula: a great cloud of gas that was blown off by an old star.
- Photosphere: the layer of a star that releases light and other energy into space.
- Prominence: an eruption of hot gas at the surface of the Sun.
- Provisional designation: a temporary name given to a newly-found object. Later a permanent name may be picked.
- Radar: radio waves used to find distances to and make maps of things.
- Regolith: loose soil on the Moon created by rocks hitting the surface at very high speed.
- Retrograde motion: a rotation that is the opposite way from the rotation of most of the Solar System.
- Retrograde orbit: an orbit that is the opposite way from the orbit of most of the planets and moons in the Solar System.
- Ring: A flat, circular band of many small, loose objects that orbit a planet.
- Rotate: to spin around on an axis.
- Satellite: an object in a stable orbit around a much larger object.
- Scarp: a type of cliff.
- Sidereal day: the time for a planet or moon to rotate so that a distant star overhead is again overhead.
- Silicate: an object composed mostly of the element silicon, which makes rocks.
- Shooting star: another name for a meteor.
- Solar day: the time for a planet or moon to rotate so that the Sun is again overhead.
- Solar wind: a very hot gas that is being blown away from the Sun at a high speed.
- Spacesuit: A special sealed suit that protects an astronaut. It has its own air supply so the astronaut can breath, and is insulated against the cold of space.
- Spectrum: the colored band of light made when white light passes through a prism.
- Star: a huge ball of gas that is so heavy that it causes nuclear reactions inside itself. This produces heat and light.
- Sulfuric acid: a strong type of acid that is used in car batteries, and contains the element sulphur.
- Supergiant: a star near the end of its life that puffs out into a huge body many times larger than a normal star.
- Surface area: the area on the outside of something.
- Tectonic Plate: a solid part of the crust that very slowly moves across the surface of a planet
- Telescope: a system of lenses or mirrors that are used to see distant objects.
- Terrestrial planets: the four planets closest to the Sun.
- Tether: A cord that is used to keep two things attached to each other, such as an astronaut to a spaceship.
- Tide: the rise in the surface caused by gravity from another object, such as the Moon or Sun.
- Tidal lock: when tides have slowed rotation so that a moon or planet is always facing the same side toward the planet or star.
- Transit: When astronomers observe one object pass in front of a larger object.
- Trojan asteroid: an asteroid in the same orbit as a planet or moon that always stays the same distance ahead or behind.
- Volcanic: something that relates to volcanoes.
- Volume: the size of a three-dimensional object.
- White dwarf: a star that has run out of fuel to burn and is slowly cooling off.
- Zone: A name used for bands of light-colored cloud layers on Jupiter.